Heat lets up a bit but storms still possible

June 25, 2009

Today's temperatures aren't expected to reach the highs of the last two days, but the thermometer could still hit 90 degrees with thunderstorms late in the morning or early in the afternoon, according to the National Weather Service.

A weather system headed into northern Illinois from the upper Mississippi Valley could produce strong winds when it hits the warm air.

"When you start to get very humid and warm conditions, that allows for greater instability in the atmosphere, so when you do develop thunderstorms, they do tend to be stronger," said Mark Ratzer, a meteorologist with the weather service's Chicago area office.

For the latest on the weather, check the Chicago Tribune's Weather Page HERE.

Wednesday saw a string of freak storms that packed a wallop, WGN-TV's Tom Skilling says.Part of a high school dugout in Burbank was toppled and a water tower on the West Side was struck by lightning as the sweltering heat spawned thunderstorms in the Chicago area.

A microburst is believed responsible for taking off part of the roof of the baseball dugout at St.Laurence High School, 5556 W. 77th Street in Burbank. A coach and a player were slightly injured.

Trees were uprooted near 79th Street and Central Avenue and power lines were downed. Light poles near the 5000 block of West 63rd Street around Midway Airport were also damaged, according to the Chicago Department of Aviation.

Wednesday's storms offered brief relief to the hottest spell of weather in the Chicago area in almost two years.

The high hit 94 degrees at O'Hare International Airport, making Tuesday and Wednesday the first time since July 8 and 9, 2007 that the temperature reached 94 two days in a row.

Although it's expected to be well above the normal high of 81, it will be far from the record high for June 25 of 103, set back in 1988. The Weather Service hasn't issued a heat or weather advisory for today, but the predicted thunderstorms could result in high winds of 60 m.p.h., hail and heavy localized rainfall and flooding.

Meanwhile, the state and local governments in Northern Illinois have designated their facilities as cooling centers this week during the heat, although some are waiting to see if the heat gets worse.

Air quality in suburban counties is expected to be less than perfect but better than Wednesday, endangering people with respiratory problems in Lake County but not other Chicago-area counties, according to the Illinois EPA.